1. Field of the Invention
The present invention relates to a slot machine in which occurrence of a winning is judged in accordance with a combination of symbols stopping at a winning line.
2. Description of the Related Art
As well known, a slot machine has a plurality of reels or a CRT. The reel is rotatable and is provided with symbols arranged on a peripheral surface thereof. On the other hand, the CRT displays the symbols on the basis of graphic data stored in ROM. The symbol displayed in the CRT is moved so as to simulate the rotation of the reel. In such a slot machine, the reels are rotated together by an operation of a start button or a start lever after inserting a coin, a token and so forth (hereinafter, coin). The reel is stopped by an operation of a stop button provided for each reel or after a predetermined time has passed. When the reels have stopped, occurrence and kind of winning is determined in accordance with a combination of the symbols stopping at a predetermined winning line. When the winning is obtained, coins, number of which is predetermined, are paid out according to the kind of the winning.
There are various kinds of winning. For example, there is a winning such that the coins, number of which is from five to fifteen, are paid out when the prescribed symbols of two or three kinds are displayed at the winning line. Besides that, there are a jackpot winning, a bonus game winning and so forth. As to the jackpot winning, a great deal of dividend is obtained when the specific symbol combination, for example, "7-7-7" is displayed along the winning line. Regarding the bonus game winning, a bonus game is given. In the bonus game, winnings occur frequently at high probability in comparison with the normal game. In such slot machine, it becomes a great pleasure for a player whether various winnings are obtained or not.
In order to increase the pleasure of the slot machine, Japanese Patent Laid-Open Publication No. 60-185579 discloses a slot machine in which a winning chance is obtained again by re-rotating the reel after it has stopped once.
Moreover, Japanese Patent Laid-Open Publication No. 7-275432 discloses a slot machine having a first reel group for normal game and a second reel group for bonus game. The second reel group is used only when the specific symbols of the first reel group are arranged along the winning line, namely, the bonus game is obtained. Such slot machine has various game modes in the bonus game.
However, regarding the slot machine in which the reel stopped once is re-rotated when the game is lost, one set of the reels is used to decide whether the chance for re-rotating the reel is given or not, besides determining whether the winning occurs or not. Accordingly, even if winning chance according to the re-rotation of the reel is taken, a feeling that the game is extended is merely given to the player. Particularly, great expectation and interest for the winning are not given to the player.
As to the slot machine employing the second reel group used only for the bonus game besides the reel for the normal game, freshness is given for the bonus game. However, while the normal game is played, this slot machine is not different from a conventional one. Further, winning probability of the bonus game is set at low so that most of the players might lose the interest before playing the bonus game utilizing the second reel group.